Abstract
In the last decade, the available shortest pulse duration from Tm doped solid state lasers strongly shortened.
The shortening was mainly done by developments of new saturable absorbers and laser crystals.
We have developed Kerr-lens mode locked Tm:Sc2O3 laser and obtained 72 fs pulses where the spectrum
of the pulses is broader than a bandwidth of used gain medium. In addition, we have developed Kerrlens
mode locked Tm:Sc2O3, Tm:Lu2O3 combined active gain media laser to overcome gain bandwidth
limitation of single gain medium and obtained pulses as short as 53 fs (sub 8 cycle). In the experiment,
we have observed unusual spectral broadening effect, which is probably related to intra-pulse stimulated
Raman scattering and could enable sub 40 fs (sub 6 cycle) pulse generation directly from Tm doped solid
state laser oscillator.
